Question: Solve for $q$ : $8 = q - 9$
Answer: Add $9$ to both sides: $ \begin{eqnarray} \\ \hphantom{8 {+ 9}} &\hphantom{=}& \hphantom{q} \\ 8 &=& q - 9 \\ \\ {+9} && {+9} \\ \end{eqnarray} $ $ \begin{eqnarray} \\ 8 {+ 9} &=& q \\ \end{eqnarray} $ Simplify. $ q = 17$